Inverter putting 250 volts on one leg

Ronbo · October 6, 2017

I have a Magnum 2812 inverter. It malfunctioned while we were away for a week. I had my SIL just turn off the breakers to the rv. When I started checking my EMS was showing 126 volts on each leg so I knew so,etching was wrong with the rv. Then I turned on any breaker I received 250 volts on one leg and 9 volts on the other leg. I new I had an open neutral. After checking a lot of stuff, I disconnected the wires to the inverter and wired them together. Magically everything started working. I began checking out everything and the only item damaged was the converter. I will not be replacing it since my inverter will also charge my batteries. I contacted Magnum and also found where I ordered the inverter from Amazon. I am still under warranty by 3 weeks. It will be going to Oklahoma City on Monday and to the shop on Tuesday for repair. The warranty will save me almost $2000. Glad I have 1000 watts of solar to charge the lithium batteries.

Chad Heiser · October 6, 2017

It will be interesting to find out what happened to the Magnum to cause this. It is the first Magnum failure I am aware of (I'm sure there have been others, but I have not heard of them). Nice thing your warranty is still good. That would have been an expensive one if not.

Al F · October 7, 2017

21 hours ago, Ronbo said:

I have a Magnum 2812 inverter. It malfunctioned while we were away for a week. I had my SIL just turn off the breakers to the rv. When I started checking my EMS was showing 126 volts on each leg so I knew so,etching was wrong with the rv. Then I turned on any breaker I received 250 volts on one leg and 9 volts on the other leg. I new I had an open neutral. After checking a lot of stuff, I disconnected the wires to the inverter and wired them together. Magically everything started working. I began checking out everything and the only item damaged was the converter. I will not be replacing it since my inverter will also charge my batteries. I contacted Magnum and also found where I ordered the inverter from Amazon. I am still under warranty by 3 weeks. It will be going to Oklahoma City on Monday and to the shop on Tuesday for repair. The warranty will save me almost $2000. Glad I have 1000 watts of solar to charge the lithium batteries.

My bad. I wasn't thinking about wiring both hot legs of 50amp service to the inverter. Sorry my reply is in error.

~~If I am understanding you correctly, you were plugged into 50amp service shore power and you had an open neutral indication.~~

~~Are you saying you had an open neutral going back to shore power caused by the inverter?~~

When you disconnected the wires to the inverter, does that mean you took the 120V single phase AC wires coming from shore power/generator and wired them to the single phase 120V AC wires which come from the inverter and goes to the 120V AC outlets in the RV?

~~Looking online at the specs for the inverter it has a single phase 120V output, so I can't see the inverter being able to generate 250VAC.~~

~~I also don't understand how the inverter can cause an open neutral.~~

~~It is confusing to me to try to understand just what happened.~~

Lou Schneider · October 7, 2017

Never mind .....

Ronbo · October 7, 2017

I am plugged into a 50 amp plug I installed. We had problems initially with an open neutral at the transformer. That was taken care of by the power company. The EMS did not give any alarm. It looks at incoming power and there was no problem with it. Although there was good power to the rv, nothing was working. I turned off all breakers. I turned on the main breaker and had 126v at each one. When I turned on any other breaker, that leg would drop to 9v and the other would go to 250v. Again, the EMS did not detect this as it was on the rv side. Everything except the water heater, washer and dryer and ac's goes through the inverter. Why the items that didn't go through the inverter wouldn't work, I don't know. When I removed the line and load wires from the inverter and connected them together, everything worked as it was supposed to. When I described it to the tech, he stated that the control board is bad. I know there are relays inside the inverter and it appears they are not operating properly to connect the loads. It gets dropped off Tuesday.

Lou Schneider · October 7, 2017

Irrelevant.

Al F · October 7, 2017

Lou,

Thank you for providing great detailed replies which corrected my erroneous reply earlier. I edited my reply and lined through my miss statements.

Ronbo · October 8, 2017

Lou I stated that everything EXCEPT washer, dryer, water heater and ac's go through the inverter. I do not have 30 amps go through the inverter. Your picture is wrong. L1, L2 and Neutral are all switched by the inverter. This is where my problem came from. It was not making continuity on the neutral.

Lou Schneider · October 8, 2017

Deleted.

Al F · October 8, 2017

While I don't have access to the main AC power distribution panel, I think you would find that the incoming pair of 50amp lines, L1 & L2 go to the the main distribution panel. In this panel you will find a string of circuit breakers on a bus bar. There would be a CB for each air conditioner, the water heater, washer dryer, etc. Most likely there is a pair of CB's for the inverter as well. Since all the CB's and the neutral return bus bar are all contained in this distribution panel and the wires going to the high current devices in the RV all attach to the distribution panel, not to the inverter, there is no high current devices, other than the microwave for the inverters transfer switch to handle.

Ronbo · October 8, 2017

Al,you are correct. I have 2 30 amp breakers feeding each leg of the inverter. That output then goes to a sub panel to supply power to the appropriate items. The high power items are powered directly from the 50 amp input through appropriate breakers.